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1 Kernel Parameters
2 ~~~~~~~~~~~~~~~~~
4 The following is a consolidated list of the kernel parameters as implemented
5 (mostly) by the __setup() macro and sorted into English Dictionary order
6 (defined as ignoring all punctuation and sorting digits before letters in a
7 case insensitive manner), and with descriptions where known.
9 Module parameters for loadable modules are specified only as the
10 parameter name with optional '=' and value as appropriate, such as:
12 modprobe usbcore blinkenlights=1
14 Module parameters for modules that are built into the kernel image
15 are specified on the kernel command line with the module name plus
16 '.' plus parameter name, with '=' and value if appropriate, such as:
18 usbcore.blinkenlights=1
20 This document may not be entirely up to date and comprehensive. The command
21 "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
22 module. Loadable modules, after being loaded into the running kernel, also
23 reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
24 parameters may be changed at runtime by the command
25 "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
27 The parameters listed below are only valid if certain kernel build options were
28 enabled and if respective hardware is present. The text in square brackets at
29 the beginning of each description states the restrictions within which a
30 parameter is applicable:
32 ACPI ACPI support is enabled.
33 AGP AGP (Accelerated Graphics Port) is enabled.
34 ALSA ALSA sound support is enabled.
35 APIC APIC support is enabled.
36 APM Advanced Power Management support is enabled.
37 AX25 Appropriate AX.25 support is enabled.
38 BLACKFIN Blackfin architecture is enabled.
39 DRM Direct Rendering Management support is enabled.
40 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
41 EFI EFI Partitioning (GPT) is enabled
42 EIDE EIDE/ATAPI support is enabled.
43 FB The frame buffer device is enabled.
44 HW Appropriate hardware is enabled.
45 IA-64 IA-64 architecture is enabled.
46 IOSCHED More than one I/O scheduler is enabled.
47 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
48 ISAPNP ISA PnP code is enabled.
49 ISDN Appropriate ISDN support is enabled.
50 JOY Appropriate joystick support is enabled.
51 LIBATA Libata driver is enabled
52 LP Printer support is enabled.
53 LOOP Loopback device support is enabled.
54 M68k M68k architecture is enabled.
55 These options have more detailed description inside of
56 Documentation/m68k/kernel-options.txt.
57 MCA MCA bus support is enabled.
58 MDA MDA console support is enabled.
59 MOUSE Appropriate mouse support is enabled.
60 MSI Message Signaled Interrupts (PCI).
61 MTD MTD (Memory Technology Device) support is enabled.
62 NET Appropriate network support is enabled.
63 NUMA NUMA support is enabled.
64 GENERIC_TIME The generic timeofday code is enabled.
65 NFS Appropriate NFS support is enabled.
66 OSS OSS sound support is enabled.
67 PV_OPS A paravirtualized kernel is enabled.
68 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
69 PARISC The PA-RISC architecture is enabled.
70 PCI PCI bus support is enabled.
71 PCIE PCI Express support is enabled.
72 PCMCIA The PCMCIA subsystem is enabled.
73 PNP Plug & Play support is enabled.
74 PPC PowerPC architecture is enabled.
75 PPT Parallel port support is enabled.
76 PS2 Appropriate PS/2 support is enabled.
77 RAM RAM disk support is enabled.
78 ROOTPLUG The example Root Plug LSM is enabled.
79 S390 S390 architecture is enabled.
80 SCSI Appropriate SCSI support is enabled.
81 A lot of drivers has their options described inside of
82 Documentation/scsi/.
83 SECURITY Different security models are enabled.
84 SELINUX SELinux support is enabled.
85 SERIAL Serial support is enabled.
86 SH SuperH architecture is enabled.
87 SMP The kernel is an SMP kernel.
88 SPARC Sparc architecture is enabled.
89 SWSUSP Software suspend is enabled.
90 TS Appropriate touchscreen support is enabled.
91 USB USB support is enabled.
92 USBHID USB Human Interface Device support is enabled.
93 V4L Video For Linux support is enabled.
94 VGA The VGA console has been enabled.
95 VT Virtual terminal support is enabled.
96 WDT Watchdog support is enabled.
97 XT IBM PC/XT MFM hard disk support is enabled.
98 X86-32 X86-32, aka i386 architecture is enabled.
99 X86-64 X86-64 architecture is enabled.
100 More X86-64 boot options can be found in
101 Documentation/x86_64/boot-options.txt .
103 In addition, the following text indicates that the option:
105 BUGS= Relates to possible processor bugs on the said processor.
106 KNL Is a kernel start-up parameter.
107 BOOT Is a boot loader parameter.
109 Parameters denoted with BOOT are actually interpreted by the boot
110 loader, and have no meaning to the kernel directly.
111 Do not modify the syntax of boot loader parameters without extreme
112 need or coordination with <Documentation/i386/boot.txt>.
114 There are also arch-specific kernel-parameters not documented here.
115 See for example <Documentation/x86_64/boot-options.txt>.
117 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
118 a trailing = on the name of any parameter states that that parameter will
119 be entered as an environment variable, whereas its absence indicates that
120 it will appear as a kernel argument readable via /proc/cmdline by programs
121 running once the system is up.
123 The number of kernel parameters is not limited, but the length of the
124 complete command line (parameters including spaces etc.) is limited to
125 a fixed number of characters. This limit depends on the architecture
126 and is between 256 and 4096 characters. It is defined in the file
127 ./include/asm/setup.h as COMMAND_LINE_SIZE.
130 acpi= [HW,ACPI,X86-64,i386]
131 Advanced Configuration and Power Interface
132 Format: { force | off | ht | strict | noirq }
133 force -- enable ACPI if default was off
134 off -- disable ACPI if default was on
135 noirq -- do not use ACPI for IRQ routing
136 ht -- run only enough ACPI to enable Hyper Threading
137 strict -- Be less tolerant of platforms that are not
138 strictly ACPI specification compliant.
140 See also Documentation/pm.txt, pci=noacpi
142 acpi_apic_instance= [ACPI, IOAPIC]
143 Format: <int>
144 2: use 2nd APIC table, if available
145 1,0: use 1st APIC table
146 default: 0
148 acpi_sleep= [HW,ACPI] Sleep options
149 Format: { s3_bios, s3_mode }
150 See Documentation/power/video.txt
152 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
153 Format: { level | edge | high | low }
155 acpi_irq_balance [HW,ACPI]
156 ACPI will balance active IRQs
157 default in APIC mode
159 acpi_irq_nobalance [HW,ACPI]
160 ACPI will not move active IRQs (default)
161 default in PIC mode
163 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
164 use by PCI
165 Format: <irq>,<irq>...
167 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
168 Format: <irq>,<irq>...
170 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
172 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
173 Format: To spoof as Windows 98: ="Microsoft Windows"
175 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
176 acpi_osi="string1" # add string1 -- only one string
177 acpi_osi="!string2" # remove built-in string2
178 acpi_osi= # disable all strings
180 acpi_serialize [HW,ACPI] force serialization of AML methods
182 acpi_skip_timer_override [HW,ACPI]
183 Recognize and ignore IRQ0/pin2 Interrupt Override.
184 For broken nForce2 BIOS resulting in XT-PIC timer.
185 acpi_use_timer_override [HW,ACPI}
186 Use timer override. For some broken Nvidia NF5 boards
187 that require a timer override, but don't have
188 HPET
190 acpi.debug_layer= [HW,ACPI]
191 Format: <int>
192 Each bit of the <int> indicates an ACPI debug layer,
193 1: enable, 0: disable. It is useful for boot time
194 debugging. After system has booted up, it can be set
195 via /sys/module/acpi/parameters/debug_layer.
196 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
197 Available bits (add the numbers together) to enable debug output
198 for specific parts of the ACPI subsystem:
199 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
200 0x10 namespace 0x20 parser 0x40 dispatcher
201 0x80 executer 0x100 resources 0x200 acpica debugger
202 0x400 os services 0x800 acpica disassembler.
203 The number can be in decimal or prefixed with 0x in hex.
204 Warning: Many of these options can produce a lot of
205 output and make your system unusable. Be very careful.
207 acpi.debug_level= [HW,ACPI]
208 Format: <int>
209 Each bit of the <int> indicates an ACPI debug level,
210 1: enable, 0: disable. It is useful for boot time
211 debugging. After system has booted up, it can be set
212 via /sys/module/acpi/parameters/debug_level.
213 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
214 Available bits (add the numbers together) to enable different
215 debug output levels of the ACPI subsystem:
216 0x01 error 0x02 warn 0x04 init 0x08 debug object
217 0x10 info 0x20 init names 0x40 parse 0x80 load
218 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
219 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
220 0x10000 resources 0x20000 user requests 0x40000 package.
221 The number can be in decimal or prefixed with 0x in hex.
222 Warning: Many of these options can produce a lot of
223 output and make your system unusable. Be very careful.
225 acpi_pm_good [X86-32,X86-64]
226 Override the pmtimer bug detection: force the kernel
227 to assume that this machine's pmtimer latches its value
228 and always returns good values.
230 agp= [AGP]
231 { off | try_unsupported }
232 off: disable AGP support
233 try_unsupported: try to drive unsupported chipsets
234 (may crash computer or cause data corruption)
236 enable_timer_pin_1 [i386,x86-64]
237 Enable PIN 1 of APIC timer
238 Can be useful to work around chipset bugs
239 (in particular on some ATI chipsets).
240 The kernel tries to set a reasonable default.
242 disable_timer_pin_1 [i386,x86-64]
243 Disable PIN 1 of APIC timer
244 Can be useful to work around chipset bugs.
246 ad1848= [HW,OSS]
247 Format: <io>,<irq>,<dma>,<dma2>,<type>
249 advansys= [HW,SCSI]
250 See header of drivers/scsi/advansys.c.
252 advwdt= [HW,WDT] Advantech WDT
253 Format: <iostart>,<iostop>
255 aedsp16= [HW,OSS] Audio Excel DSP 16
256 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
257 See also header of sound/oss/aedsp16.c.
259 aha152x= [HW,SCSI]
260 See Documentation/scsi/aha152x.txt.
262 aha1542= [HW,SCSI]
263 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
265 aic7xxx= [HW,SCSI]
266 See Documentation/scsi/aic7xxx.txt.
268 aic79xx= [HW,SCSI]
269 See Documentation/scsi/aic79xx.txt.
271 amijoy.map= [HW,JOY] Amiga joystick support
272 Map of devices attached to JOY0DAT and JOY1DAT
273 Format: <a>,<b>
274 See also Documentation/kernel/input/joystick.txt
276 analog.map= [HW,JOY] Analog joystick and gamepad support
277 Specifies type or capabilities of an analog joystick
278 connected to one of 16 gameports
279 Format: <type1>,<type2>,..<type16>
281 apc= [HW,SPARC]
282 Power management functions (SPARCstation-4/5 + deriv.)
283 Format: noidle
284 Disable APC CPU standby support. SPARCstation-Fox does
285 not play well with APC CPU idle - disable it if you have
286 APC and your system crashes randomly.
288 apic= [APIC,i386] Advanced Programmable Interrupt Controller
289 Change the output verbosity whilst booting
290 Format: { quiet (default) | verbose | debug }
291 Change the amount of debugging information output
292 when initialising the APIC and IO-APIC components.
294 apm= [APM] Advanced Power Management
295 See header of arch/i386/kernel/apm.c.
297 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
298 Format: <io>,<irq>,<nodeID>
300 ataflop= [HW,M68k]
302 atarimouse= [HW,MOUSE] Atari Mouse
304 atascsi= [HW,SCSI] Atari SCSI
306 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
307 EzKey and similar keyboards
309 atkbd.reset= [HW] Reset keyboard during initialization
311 atkbd.set= [HW] Select keyboard code set
312 Format: <int> (2 = AT (default), 3 = PS/2)
314 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
315 keyboards
317 atkbd.softraw= [HW] Choose between synthetic and real raw mode
318 Format: <bool> (0 = real, 1 = synthetic (default))
320 atkbd.softrepeat= [HW]
321 Use software keyboard repeat
323 autotest [IA64]
325 baycom_epp= [HW,AX25]
326 Format: <io>,<mode>
328 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
329 Format: <io>,<mode>
330 See header of drivers/net/hamradio/baycom_par.c.
332 baycom_ser_fdx= [HW,AX25]
333 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
334 Format: <io>,<irq>,<mode>[,<baud>]
335 See header of drivers/net/hamradio/baycom_ser_fdx.c.
337 baycom_ser_hdx= [HW,AX25]
338 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
339 Format: <io>,<irq>,<mode>
340 See header of drivers/net/hamradio/baycom_ser_hdx.c.
342 boot_delay= Milliseconds to delay each printk during boot.
343 Values larger than 10 seconds (10000) are changed to
344 no delay (0).
345 Format: integer
347 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
348 bttv.radio= Most important insmod options are available as
349 kernel args too.
350 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
351 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
353 BusLogic= [HW,SCSI]
354 See drivers/scsi/BusLogic.c, comment before function
355 BusLogic_ParseDriverOptions().
357 c101= [NET] Moxa C101 synchronous serial card
359 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
360 Sometimes CPU hardware bugs make them report the cache
361 size incorrectly. The kernel will attempt work arounds
362 to fix known problems, but for some CPUs it is not
363 possible to determine what the correct size should be.
364 This option provides an override for these situations.
366 capability.disable=
367 [SECURITY] Disable capabilities. This would normally
368 be used only if an alternative security model is to be
369 configured. Potentially dangerous and should only be
370 used if you are entirely sure of the consequences.
372 chandev= [HW,NET] Generic channel device initialisation
374 checkreqprot [SELINUX] Set initial checkreqprot flag value.
375 Format: { "0" | "1" }
376 See security/selinux/Kconfig help text.
377 0 -- check protection applied by kernel (includes
378 any implied execute protection).
379 1 -- check protection requested by application.
380 Default value is set via a kernel config option.
381 Value can be changed at runtime via
382 /selinux/checkreqprot.
384 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
385 [Deprecated]
386 Forces specified clocksource (if available) to be used
387 when calculating gettimeofday(). If specified
388 clocksource is not available, it defaults to PIT.
389 Format: { pit | tsc | cyclone | pmtmr }
391 clocksource= [GENERIC_TIME] Override the default clocksource
392 Format: <string>
393 Override the default clocksource and use the clocksource
394 with the name specified.
395 Some clocksource names to choose from, depending on
396 the platform:
397 [all] jiffies (this is the base, fallback clocksource)
398 [ACPI] acpi_pm
399 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
400 pxa_timer,timer3,32k_counter,timer0_1
401 [AVR32] avr32
402 [X86-32] pit,hpet,tsc,vmi-timer;
403 scx200_hrt on Geode; cyclone on IBM x440
404 [MIPS] MIPS
405 [PARISC] cr16
406 [S390] tod
407 [SH] SuperH
408 [SPARC64] tick
409 [X86-64] hpet,tsc
411 code_bytes [IA32] How many bytes of object code to print in an
412 oops report.
413 Range: 0 - 8192
414 Default: 64
416 disable_8254_timer
417 enable_8254_timer
418 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
419 over the 8254 in addition to over the IO-APIC. The
420 kernel tries to set a sensible default.
422 hpet= [X86-32,HPET] option to control HPET usage
423 Format: { enable (default) | disable | force }
424 disable: disable HPET and use PIT instead
425 force: allow force enabled of undocumented chips (ICH4,
426 VIA, nVidia)
428 com20020= [HW,NET] ARCnet - COM20020 chipset
429 Format:
430 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
432 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
433 Format: <io>[,<irq>]
435 com90xx= [HW,NET]
436 ARCnet - COM90xx chipset (memory-mapped buffers)
437 Format: <io>[,<irq>[,<memstart>]]
439 condev= [HW,S390] console device
440 conmode=
442 console= [KNL] Output console device and options.
444 tty<n> Use the virtual console device <n>.
446 ttyS<n>[,options]
447 ttyUSB0[,options]
448 Use the specified serial port. The options are of
449 the form "bbbbpnf", where "bbbb" is the baud rate,
450 "p" is parity ("n", "o", or "e"), "n" is number of
451 bits, and "f" is flow control ("r" for RTS or
452 omit it). Default is "9600n8".
454 See Documentation/serial-console.txt for more
455 information. See
456 Documentation/networking/netconsole.txt for an
457 alternative.
459 uart[8250],io,<addr>[,options]
460 uart[8250],mmio,<addr>[,options]
461 Start an early, polled-mode console on the 8250/16550
462 UART at the specified I/O port or MMIO address,
463 switching to the matching ttyS device later. The
464 options are the same as for ttyS, above.
466 earlycon= [KNL] Output early console device and options.
467 uart[8250],io,<addr>[,options]
468 uart[8250],mmio,<addr>[,options]
469 Start an early, polled-mode console on the 8250/16550
470 UART at the specified I/O port or MMIO address.
471 The options are the same as for ttyS, above.
473 no_console_suspend
474 [HW] Never suspend the console
475 Disable suspending of consoles during suspend and
476 hibernate operations. Once disabled, debugging
477 messages can reach various consoles while the rest
478 of the system is being put to sleep (ie, while
479 debugging driver suspend/resume hooks). This may
480 not work reliably with all consoles, but is known
481 to work with serial and VGA consoles.
483 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
484 Format:
485 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
487 crashkernel=nn[KMG]@ss[KMG]
488 [KNL] Reserve a chunk of physical memory to
489 hold a kernel to switch to with kexec on panic.
491 crashkernel=range1:size1[,range2:size2,...][@offset]
492 [KNL] Same as above, but depends on the memory
493 in the running system. The syntax of range is
494 start-[end] where start and end are both
495 a memory unit (amount[KMG]). See also
496 Documentation/kdump/kdump.txt for a example.
498 cs4232= [HW,OSS]
499 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
501 cs89x0_dma= [HW,NET]
502 Format: <dma>
504 cs89x0_media= [HW,NET]
505 Format: { rj45 | aui | bnc }
507 dasd= [HW,NET]
508 See header of drivers/s390/block/dasd_devmap.c.
510 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
511 (one device per port)
512 Format: <port#>,<type>
513 See also Documentation/input/joystick-parport.txt
515 debug [KNL] Enable kernel debugging (events log level).
517 debug_locks_verbose=
518 [KNL] verbose self-tests
519 Format=<0|1>
520 Print debugging info while doing the locking API
521 self-tests.
522 We default to 0 (no extra messages), setting it to
523 1 will print _a lot_ more information - normally
524 only useful to kernel developers.
526 decnet= [HW,NET]
527 Format: <area>[,<node>]
528 See also Documentation/networking/decnet.txt.
530 default_blu= [VT]
531 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
532 Change the default blue palette of the console.
533 This is a 16-member array composed of values
534 ranging from 0-255.
536 default_grn= [VT]
537 Format: <green0>,<green1>,<green2>,...,<green15>
538 Change the default green palette of the console.
539 This is a 16-member array composed of values
540 ranging from 0-255.
542 default_red= [VT]
543 Format: <red0>,<red1>,<red2>,...,<red15>
544 Change the default red palette of the console.
545 This is a 16-member array composed of values
546 ranging from 0-255.
548 default_utf8= [VT]
549 Format=<0|1>
550 Set system-wide default UTF-8 mode for all tty's.
551 Default is 0 and by setting to 1, it enables UTF-8
552 mode for all newly opened or allocated terminals.
554 dhash_entries= [KNL]
555 Set number of hash buckets for dentry cache.
557 digi= [HW,SERIAL]
558 IO parameters + enable/disable command.
560 digiepca= [HW,SERIAL]
561 See drivers/char/README.epca and
562 Documentation/digiepca.txt.
564 dmasound= [HW,OSS] Sound subsystem buffers
566 dscc4.setup= [NET]
568 dtc3181e= [HW,SCSI]
570 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
571 earlyprintk=vga
572 earlyprintk=serial[,ttySn[,baudrate]]
574 Append ",keep" to not disable it when the real console
575 takes over.
577 Only vga or serial at a time, not both.
579 Currently only ttyS0 and ttyS1 are supported.
581 Interaction with the standard serial driver is not
582 very good.
584 The VGA output is eventually overwritten by the real
585 console.
587 eata= [HW,SCSI]
589 edd= [EDD]
590 Format: {"of[f]" | "sk[ipmbr]"}
591 See comment in arch/i386/boot/edd.S
593 eisa_irq_edge= [PARISC,HW]
594 See header of drivers/parisc/eisa.c.
596 elanfreq= [X86-32]
597 See comment before function elanfreq_setup() in
598 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
600 elevator= [IOSCHED]
601 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
602 See Documentation/block/as-iosched.txt and
603 Documentation/block/deadline-iosched.txt for details.
605 elfcorehdr= [X86-32, X86_64]
606 Specifies physical address of start of kernel core
607 image elf header. Generally kexec loader will
608 pass this option to capture kernel.
609 See Documentation/kdump/kdump.txt for details.
611 enforcing [SELINUX] Set initial enforcing status.
612 Format: {"0" | "1"}
613 See security/selinux/Kconfig help text.
614 0 -- permissive (log only, no denials).
615 1 -- enforcing (deny and log).
616 Default value is 0.
617 Value can be changed at runtime via /selinux/enforce.
619 es1371= [HW,OSS]
620 Format: <spdif>,[<nomix>,[<amplifier>]]
621 See also header of sound/oss/es1371.c.
623 ether= [HW,NET] Ethernet cards parameters
624 This option is obsoleted by the "netdev=" option, which
625 has equivalent usage. See its documentation for details.
627 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
628 Format: <io>[,<irq>]
630 failslab=
631 fail_page_alloc=
632 fail_make_request=[KNL]
633 General fault injection mechanism.
634 Format: <interval>,<probability>,<space>,<times>
635 See also /Documentation/fault-injection/.
637 fd_mcs= [HW,SCSI]
638 See header of drivers/scsi/fd_mcs.c.
640 fdomain= [HW,SCSI]
641 See header of drivers/scsi/fdomain.c.
643 floppy= [HW]
644 See Documentation/floppy.txt.
646 gamecon.map[2|3]=
647 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
648 support via parallel port (up to 5 devices per port)
649 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
650 See also Documentation/input/joystick-parport.txt
652 gamma= [HW,DRM]
654 gdth= [HW,SCSI]
655 See header of drivers/scsi/gdth.c.
657 gpt [EFI] Forces disk with valid GPT signature but
658 invalid Protective MBR to be treated as GPT.
660 gvp11= [HW,SCSI]
662 hashdist= [KNL,NUMA] Large hashes allocated during boot
663 are distributed across NUMA nodes. Defaults on
664 for IA-64, off otherwise.
665 Format: 0 | 1 (for off | on)
667 hcl= [IA-64] SGI's Hardware Graph compatibility layer
669 hd= [EIDE] (E)IDE hard drive subsystem geometry
670 Format: <cyl>,<head>,<sect>
672 hd?= [HW] (E)IDE subsystem
673 hd?lun= See Documentation/ide.txt.
675 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
676 size of <nn>. This works even on boxes that have no
677 highmem otherwise. This also works to reduce highmem
678 size on bigger boxes.
680 highres= [KNL] Enable/disable high resolution timer mode.
681 Valid parameters: "on", "off"
682 Default: "on"
684 hisax= [HW,ISDN]
685 See Documentation/isdn/README.HiSax.
687 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
689 i8042.direct [HW] Put keyboard port into non-translated mode
690 i8042.dumbkbd [HW] Pretend that controller can only read data from
691 keyboard and cannot control its state
692 (Don't attempt to blink the leds)
693 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
694 i8042.nokbd [HW] Don't check/create keyboard port
695 i8042.nomux [HW] Don't check presence of an active multiplexing
696 controller
697 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
698 controllers
699 i8042.panicblink=
700 [HW] Frequency with which keyboard LEDs should blink
701 when kernel panics (default is 0.5 sec)
702 i8042.reset [HW] Reset the controller during init and cleanup
703 i8042.unlock [HW] Unlock (ignore) the keylock
705 i810= [HW,DRM]
707 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
708 indicates that the driver is running on unsupported
709 hardware.
710 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
711 does not match list of supported models.
712 i8k.power_status
713 [HW] Report power status in /proc/i8k
714 (disabled by default)
715 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
716 capability is set.
718 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
719 See Documentation/mca.txt.
721 icn= [HW,ISDN]
722 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
724 ide= [HW] (E)IDE subsystem
725 Format: ide=nodma or ide=doubler or ide=reverse
726 See Documentation/ide.txt.
728 ide?= [HW] (E)IDE subsystem
729 Format: ide?=noprobe or chipset specific parameters.
730 See Documentation/ide.txt.
732 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
733 See Documentation/ide.txt.
735 idle= [X86]
736 Format: idle=poll or idle=mwait
737 Poll forces a polling idle loop that can slightly improves the performance
738 of waking up a idle CPU, but will use a lot of power and make the system
739 run hot. Not recommended.
740 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
741 to not use it because it doesn't save as much power as a normal idle
742 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
743 as idle=poll.
745 ignore_loglevel [KNL]
746 Ignore loglevel setting - this will print /all/
747 kernel messages to the console. Useful for debugging.
749 ihash_entries= [KNL]
750 Set number of hash buckets for inode cache.
752 in2000= [HW,SCSI]
753 See header of drivers/scsi/in2000.c.
755 init= [KNL]
756 Format: <full_path>
757 Run specified binary instead of /sbin/init as init
758 process.
760 initcall_debug [KNL] Trace initcalls as they are executed. Useful
761 for working out where the kernel is dying during
762 startup.
764 initrd= [BOOT] Specify the location of the initial ramdisk
766 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
767 Format: <irq>
769 inttest= [IA64]
771 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
772 off
773 Disable intel iommu driver.
774 igfx_off [Default Off]
775 By default, gfx is mapped as normal device. If a gfx
776 device has a dedicated DMAR unit, the DMAR unit is
777 bypassed by not enabling DMAR with this option. In
778 this case, gfx device will use physical address for
779 DMA.
780 forcedac [x86_64]
781 With this option iommu will not optimize to look
782 for io virtual address below 32 bit forcing dual
783 address cycle on pci bus for cards supporting greater
784 than 32 bit addressing. The default is to look
785 for translation below 32 bit and if not available
786 then look in the higher range.
788 io7= [HW] IO7 for Marvel based alpha systems
789 See comment before marvel_specify_io7 in
790 arch/alpha/kernel/core_marvel.c.
792 ip= [IP_PNP]
793 See Documentation/nfsroot.txt.
795 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
796 See comment before ip2_setup() in
797 drivers/char/ip2/ip2base.c.
799 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
800 See header of drivers/scsi/ips.c.
802 ports= [IP_VS_FTP] IPVS ftp helper module
803 Default is 21.
804 Up to 8 (IP_VS_APP_MAX_PORTS) ports
805 may be specified.
806 Format: <port>,<port>....
808 irqfixup [HW]
809 When an interrupt is not handled search all handlers
810 for it. Intended to get systems with badly broken
811 firmware running.
813 irqpoll [HW]
814 When an interrupt is not handled search all handlers
815 for it. Also check all handlers each timer
816 interrupt. Intended to get systems with badly broken
817 firmware running.
819 isapnp= [ISAPNP]
820 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
822 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
823 Format:
824 <cpu number>,...,<cpu number>
825 or
826 <cpu number>-<cpu number> (must be a positive range in ascending order)
827 or a mixture
828 <cpu number>,...,<cpu number>-<cpu number>
829 This option can be used to specify one or more CPUs
830 to isolate from the general SMP balancing and scheduling
831 algorithms. The only way to move a process onto or off
832 an "isolated" CPU is via the CPU affinity syscalls.
833 <cpu number> begins at 0 and the maximum value is
834 "number of CPUs in system - 1".
836 This option is the preferred way to isolate CPUs. The
837 alternative -- manually setting the CPU mask of all
838 tasks in the system -- can cause problems and
839 suboptimal load balancer performance.
841 iucv= [HW,NET]
843 js= [HW,JOY] Analog joystick
844 See Documentation/input/joystick.txt.
846 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
847 specifies the amount of memory usable by the kernel
848 for non-movable allocations. The requested amount is
849 spread evenly throughout all nodes in the system. The
850 remaining memory in each node is used for Movable
851 pages. In the event, a node is too small to have both
852 kernelcore and Movable pages, kernelcore pages will
853 take priority and other nodes will have a larger number
854 of kernelcore pages. The Movable zone is used for the
855 allocation of pages that may be reclaimed or moved
856 by the page migration subsystem. This means that
857 HugeTLB pages may not be allocated from this zone.
858 Note that allocations like PTEs-from-HighMem still
859 use the HighMem zone if it exists, and the Normal
860 zone if it does not.
862 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
863 is similar to kernelcore except it specifies the
864 amount of memory used for migratable allocations.
865 If both kernelcore and movablecore is specified,
866 then kernelcore will be at *least* the specified
867 value but may be more. If movablecore on its own
868 is specified, the administrator must be careful
869 that the amount of memory usable for all allocations
870 is not too small.
872 keepinitrd [HW,ARM]
874 kstack=N [X86-32,X86-64] Print N words from the kernel stack
875 in oops dumps.
877 l2cr= [PPC]
879 lapic [X86-32,APIC] Enable the local APIC even if BIOS
880 disabled it.
882 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
883 C2 power state.
885 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
886 when set.
887 Format: <int>
889 load_ramdisk= [RAM] List of ramdisks to load from floppy
890 See Documentation/ramdisk.txt.
892 lockd.nlm_grace_period=P [NFS] Assign grace period.
893 Format: <integer>
895 lockd.nlm_tcpport=N [NFS] Assign TCP port.
896 Format: <integer>
898 lockd.nlm_timeout=T [NFS] Assign timeout value.
899 Format: <integer>
901 lockd.nlm_udpport=M [NFS] Assign UDP port.
902 Format: <integer>
904 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
905 Format: <irq>
907 loglevel= All Kernel Messages with a loglevel smaller than the
908 console loglevel will be printed to the console. It can
909 also be changed with klogd or other programs. The
910 loglevels are defined as follows:
912 0 (KERN_EMERG) system is unusable
913 1 (KERN_ALERT) action must be taken immediately
914 2 (KERN_CRIT) critical conditions
915 3 (KERN_ERR) error conditions
916 4 (KERN_WARNING) warning conditions
917 5 (KERN_NOTICE) normal but significant condition
918 6 (KERN_INFO) informational
919 7 (KERN_DEBUG) debug-level messages
921 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
922 Format: { n | nk | nM }
923 n must be a power of two. The default size
924 is set in the kernel config file.
926 logo.nologo [FB] Disables display of the built-in Linux logo.
927 This may be used to provide more screen space for
928 kernel log messages and is useful when debugging
929 kernel boot problems.
931 lp=0 [LP] Specify parallel ports to use, e.g,
932 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
933 lp=reset first parallel port). 'lp=0' disables the
934 lp=auto printer driver. 'lp=reset' (which can be
935 specified in addition to the ports) causes
936 attached printers to be reset. Using
937 lp=port1,port2,... specifies the parallel ports
938 to associate lp devices with, starting with
939 lp0. A port specification may be 'none' to skip
940 that lp device, or a parport name such as
941 'parport0'. Specifying 'lp=auto' instead of a
942 port specification list means that device IDs
943 from each port should be examined, to see if
944 an IEEE 1284-compliant printer is attached; if
945 so, the driver will manage that printer.
946 See also header of drivers/char/lp.c.
948 lpj=n [KNL]
949 Sets loops_per_jiffy to given constant, thus avoiding
950 time-consuming boot-time autodetection (up to 250 ms per
951 CPU). 0 enables autodetection (default). To determine
952 the correct value for your kernel, boot with normal
953 autodetection and see what value is printed. Note that
954 on SMP systems the preset will be applied to all CPUs,
955 which is likely to cause problems if your CPUs need
956 significantly divergent settings. An incorrect value
957 will cause delays in the kernel to be wrong, leading to
958 unpredictable I/O errors and other breakage. Although
959 unlikely, in the extreme case this might damage your
960 hardware.
962 ltpc= [NET]
963 Format: <io>,<irq>,<dma>
965 mac5380= [HW,SCSI] Format:
966 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
968 mac53c9x= [HW,SCSI] Format:
969 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
971 machvec= [IA64] Force the use of a particular machine-vector
972 (machvec) in a generic kernel.
973 Example: machvec=hpzx1_swiotlb
975 max_loop= [LOOP] Maximum number of loopback devices that can
976 be mounted
977 Format: <1-256>
979 maxcpus= [SMP] Maximum number of processors that an SMP kernel
980 should make use of. maxcpus=n : n >= 0 limits the
981 kernel to using 'n' processors. n=0 is a special case,
982 it is equivalent to "nosmp", which also disables
983 the IO APIC.
985 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
986 equal to this physical address is ignored.
988 max_luns= [SCSI] Maximum number of LUNs to probe.
989 Should be between 1 and 2^32-1.
991 max_report_luns=
992 [SCSI] Maximum number of LUNs received.
993 Should be between 1 and 16384.
995 mca-pentium [BUGS=X86-32]
997 mcatest= [IA-64]
999 mce [X86-32] Machine Check Exception
1001 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1003 md= [HW] RAID subsystems devices and level
1004 See Documentation/md.txt.
1006 mdacon= [MDA]
1007 Format: <first>,<last>
1008 Specifies range of consoles to be captured by the MDA.
1010 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1011 Amount of memory to be used when the kernel is not able
1012 to see the whole system memory or for test.
1013 [X86-32] Use together with memmap= to avoid physical
1014 address space collisions. Without memmap= PCI devices
1015 could be placed at addresses belonging to unused RAM.
1017 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1018 memory.
1020 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1021 E820 memory map, as specified by the user.
1022 Such memmap=exactmap lines can be constructed based on
1023 BIOS output or other requirements. See the memmap=nn@ss
1024 option description.
1026 memmap=nn[KMG]@ss[KMG]
1027 [KNL] Force usage of a specific region of memory
1028 Region of memory to be used, from ss to ss+nn.
1030 memmap=nn[KMG]#ss[KMG]
1031 [KNL,ACPI] Mark specific memory as ACPI data.
1032 Region of memory to be used, from ss to ss+nn.
1034 memmap=nn[KMG]$ss[KMG]
1035 [KNL,ACPI] Mark specific memory as reserved.
1036 Region of memory to be used, from ss to ss+nn.
1038 meye.*= [HW] Set MotionEye Camera parameters
1039 See Documentation/video4linux/meye.txt.
1041 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1042 Multi-Function General Purpose Timers on AMD Geode
1043 platforms.
1045 mga= [HW,DRM]
1047 mousedev.tap_time=
1048 [MOUSE] Maximum time between finger touching and
1049 leaving touchpad surface for touch to be considered
1050 a tap and be reported as a left button click (for
1051 touchpads working in absolute mode only).
1052 Format: <msecs>
1053 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1054 reporting absolute coordinates, such as tablets
1055 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1056 reporting absolute coordinates, such as tablets
1058 mpu401= [HW,OSS]
1059 Format: <io>,<irq>
1061 MTD_Partition= [MTD]
1062 Format: <name>,<region-number>,<size>,<offset>
1064 MTD_Region= [MTD] Format:
1065 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1067 mtdparts= [MTD]
1068 See drivers/mtd/cmdlinepart.c.
1070 mtouchusb.raw_coordinates=
1071 [HW] Make the MicroTouch USB driver use raw coordinates
1072 ('y', default) or cooked coordinates ('n')
1074 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1076 NCR_D700= [HW,SCSI]
1077 See header of drivers/scsi/NCR_D700.c.
1079 ncr5380= [HW,SCSI]
1081 ncr53c400= [HW,SCSI]
1083 ncr53c400a= [HW,SCSI]
1085 ncr53c406a= [HW,SCSI]
1087 ncr53c8xx= [HW,SCSI]
1089 netdev= [NET] Network devices parameters
1090 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1091 Note that mem_start is often overloaded to mean
1092 something different and driver-specific.
1093 This usage is only documented in each driver source
1094 file if at all.
1096 nfsaddrs= [NFS]
1097 See Documentation/nfsroot.txt.
1099 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1100 See Documentation/nfsroot.txt.
1102 nfs.callback_tcpport=
1103 [NFS] set the TCP port on which the NFSv4 callback
1104 channel should listen.
1106 nfs.idmap_cache_timeout=
1107 [NFS] set the maximum lifetime for idmapper cache
1108 entries.
1110 nfs.enable_ino64=
1111 [NFS] enable 64-bit inode numbers.
1112 If zero, the NFS client will fake up a 32-bit inode
1113 number for the readdir() and stat() syscalls instead
1114 of returning the full 64-bit number.
1115 The default is to return 64-bit inode numbers.
1117 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1119 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1120 emulation library even if a 387 maths coprocessor
1121 is present.
1123 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1124 caches in the slab allocator. Saves per-node memory,
1125 but will impact performance.
1127 noalign [KNL,ARM]
1129 noapic [SMP,APIC] Tells the kernel to not make use of any
1130 IOAPICs that may be present in the system.
1132 nobats [PPC] Do not use BATs for mapping kernel lowmem
1133 on "Classic" PPC cores.
1135 nocache [ARM]
1137 nodelayacct [KNL] Disable per-task delay accounting
1139 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1141 noexec [IA-64]
1143 noexec [X86-32,X86-64]
1144 noexec=on: enable non-executable mappings (default)
1145 noexec=off: disable nn-executable mappings
1147 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1148 register save and restore. The kernel will only save
1149 legacy floating-point registers on task switch.
1151 nohlt [BUGS=ARM]
1153 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1154 instruction doesn't work correctly and not to
1155 use it.
1157 nohalt [IA-64] Tells the kernel not to use the power saving
1158 function PAL_HALT_LIGHT when idle. This increases
1159 power-consumption. On the positive side, it reduces
1160 interrupt wake-up latency, which may improve performance
1161 in certain environments such as networked servers or
1162 real-time systems.
1164 nohz= [KNL] Boottime enable/disable dynamic ticks
1165 Valid arguments: on, off
1166 Default: on
1168 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1170 noirqdebug [X86-32] Disables the code which attempts to detect and
1171 disable unhandled interrupt sources.
1173 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1174 broken timer IRQ sources.
1176 noisapnp [ISAPNP] Disables ISA PnP code.
1178 noinitrd [RAM] Tells the kernel not to load any configured
1179 initial RAM disk.
1181 nointroute [IA-64]
1183 nojitter [IA64] Disables jitter checking for ITC timers.
1185 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1187 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1189 noltlbs [PPC] Do not use large page/tlb entries for kernel
1190 lowmem mapping on PPC40x.
1192 nomca [IA-64] Disable machine check abort handling
1194 nomce [X86-32] Machine Check Exception
1196 nomfgpt [X86-32] Disable Multi-Function General Purpose
1197 Timer usage (for AMD Geode machines).
1199 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1201 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1202 with UP alternatives
1204 noresidual [PPC] Don't use residual data on PReP machines.
1206 noresume [SWSUSP] Disables resume and restores original swap
1207 space.
1209 no-scroll [VGA] Disables scrollback.
1210 This is required for the Braillex ib80-piezo Braille
1211 reader made by F.H. Papenmeier (Germany).
1213 nosbagart [IA-64]
1215 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1217 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1218 and disable the IO APIC. legacy for "maxcpus=0".
1220 nosoftlockup [KNL] Disable the soft-lockup detector.
1222 nosync [HW,M68K] Disables sync negotiation for all devices.
1224 notsc [BUGS=X86-32] Disable Time Stamp Counter
1226 nousb [USB] Disable the USB subsystem
1228 nowb [ARM]
1230 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1231 one of ['zone', 'node', 'default'] can be specified
1232 This can be set from sysctl after boot.
1233 See Documentation/sysctl/vm.txt for details.
1235 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1237 opl3= [HW,OSS]
1238 Format: <io>
1240 oprofile.timer= [HW]
1241 Use timer interrupt instead of performance counters
1243 osst= [HW,SCSI] SCSI Tape Driver
1244 Format: <buffer_size>,<write_threshold>
1245 See also Documentation/scsi/st.txt.
1247 panic= [KNL] Kernel behaviour on panic
1248 Format: <timeout>
1250 parkbd.port= [HW] Parallel port number the keyboard adapter is
1251 connected to, default is 0.
1252 Format: <parport#>
1253 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1254 0 for XT, 1 for AT (default is AT).
1255 Format: <mode>
1257 parport= [HW,PPT] Specify parallel ports. 0 disables.
1258 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1259 Use 'auto' to force the driver to use any
1260 IRQ/DMA settings detected (the default is to
1261 ignore detected IRQ/DMA settings because of
1262 possible conflicts). You can specify the base
1263 address, IRQ, and DMA settings; IRQ and DMA
1264 should be numbers, or 'auto' (for using detected
1265 settings on that particular port), or 'nofifo'
1266 (to avoid using a FIFO even if it is detected).
1267 Parallel ports are assigned in the order they
1268 are specified on the command line, starting
1269 with parport0.
1271 parport_init_mode= [HW,PPT]
1272 Configure VIA parallel port to operate in
1273 a specific mode. This is necessary on Pegasos
1274 computer where firmware has no options for setting
1275 up parallel port mode and sets it to spp.
1276 Currently this function knows 686a and 8231 chips.
1277 Format: [spp|ps2|epp|ecp|ecpepp]
1279 pas2= [HW,OSS] Format:
1280 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1282 pas16= [HW,SCSI]
1283 See header of drivers/scsi/pas16.c.
1285 pause_on_oops=
1286 Halt all CPUs after the first oops has been printed for
1287 the specified number of seconds. This is to be used if
1288 your oopses keep scrolling off the screen.
1290 pcbit= [HW,ISDN]
1292 pcd. [PARIDE]
1293 See header of drivers/block/paride/pcd.c.
1294 See also Documentation/paride.txt.
1296 pci=option[,option...] [PCI] various PCI subsystem options:
1297 off [X86-32] don't probe for the PCI bus
1298 bios [X86-32] force use of PCI BIOS, don't access
1299 the hardware directly. Use this if your machine
1300 has a non-standard PCI host bridge.
1301 nobios [X86-32] disallow use of PCI BIOS, only direct
1302 hardware access methods are allowed. Use this
1303 if you experience crashes upon bootup and you
1304 suspect they are caused by the BIOS.
1305 conf1 [X86-32] Force use of PCI Configuration
1306 Mechanism 1.
1307 conf2 [X86-32] Force use of PCI Configuration
1308 Mechanism 2.
1309 noaer [PCIE] If the PCIEAER kernel config parameter is
1310 enabled, this kernel boot option can be used to
1311 disable the use of PCIE advanced error reporting.
1312 nodomains [PCI] Disable support for multiple PCI
1313 root domains (aka PCI segments, in ACPI-speak).
1314 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1315 Configuration
1316 nomsi [MSI] If the PCI_MSI kernel config parameter is
1317 enabled, this kernel boot option can be used to
1318 disable the use of MSI interrupts system-wide.
1319 nosort [X86-32] Don't sort PCI devices according to
1320 order given by the PCI BIOS. This sorting is
1321 done to get a device order compatible with
1322 older kernels.
1323 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1324 routing table. These calls are known to be buggy
1325 on several machines and they hang the machine
1326 when used, but on other computers it's the only
1327 way to get the interrupt routing table. Try
1328 this option if the kernel is unable to allocate
1329 IRQs or discover secondary PCI buses on your
1330 motherboard.
1331 rom [X86-32] Assign address space to expansion ROMs.
1332 Use with caution as certain devices share
1333 address decoders between ROMs and other
1334 resources.
1335 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1336 assigned automatically to PCI devices. You can
1337 make the kernel exclude IRQs of your ISA cards
1338 this way.
1339 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1340 of the PIRQ table (normally generated
1341 by the BIOS) if it is outside the
1342 F0000h-100000h range.
1343 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1344 useful if the kernel is unable to find your
1345 secondary buses and you want to tell it
1346 explicitly which ones they are.
1347 assign-busses [X86-32] Always assign all PCI bus
1348 numbers ourselves, overriding
1349 whatever the firmware may have done.
1350 usepirqmask [X86-32] Honor the possible IRQ mask stored
1351 in the BIOS $PIR table. This is needed on
1352 some systems with broken BIOSes, notably
1353 some HP Pavilion N5400 and Omnibook XE3
1354 notebooks. This will have no effect if ACPI
1355 IRQ routing is enabled.
1356 noacpi [X86-32] Do not use ACPI for IRQ routing
1357 or for PCI scanning.
1358 use_crs [X86-32] Use _CRS for PCI resource
1359 allocation.
1360 routeirq Do IRQ routing for all PCI devices.
1361 This is normally done in pci_enable_device(),
1362 so this option is a temporary workaround
1363 for broken drivers that don't call it.
1364 firmware [ARM] Do not re-enumerate the bus but instead
1365 just use the configuration from the
1366 bootloader. This is currently used on
1367 IXP2000 systems where the bus has to be
1368 configured a certain way for adjunct CPUs.
1369 noearly [X86] Don't do any early type 1 scanning.
1370 This might help on some broken boards which
1371 machine check when some devices' config space
1372 is read. But various workarounds are disabled
1373 and some IOMMU drivers will not work.
1374 bfsort Sort PCI devices into breadth-first order.
1375 This sorting is done to get a device
1376 order compatible with older (<= 2.4) kernels.
1377 nobfsort Don't sort PCI devices into breadth-first order.
1378 cbiosize=nn[KMG] The fixed amount of bus space which is
1379 reserved for the CardBus bridge's IO window.
1380 The default value is 256 bytes.
1381 cbmemsize=nn[KMG] The fixed amount of bus space which is
1382 reserved for the CardBus bridge's memory
1383 window. The default value is 64 megabytes.
1385 pcmv= [HW,PCMCIA] BadgePAD 4
1387 pd. [PARIDE]
1388 See Documentation/paride.txt.
1390 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1391 boot time.
1392 Format: { 0 | 1 }
1393 See arch/parisc/kernel/pdc_chassis.c
1395 pf. [PARIDE]
1396 See Documentation/paride.txt.
1398 pg. [PARIDE]
1399 See Documentation/paride.txt.
1401 pirq= [SMP,APIC] Manual mp-table setup
1402 See Documentation/i386/IO-APIC.txt.
1404 plip= [PPT,NET] Parallel port network link
1405 Format: { parport<nr> | timid | 0 }
1406 See also Documentation/parport.txt.
1408 pnp= [PNP] PNP subsystem options:
1409 no_reservations Don't reserve resources used by PNP devices
1410 This is for working around problems where a
1411 driver uses a PNP device without using the PNP
1412 core. Typical symptom is that the driver can't
1413 reserve the resources it needs. Please report
1414 these issues.
1416 pnpacpi= [ACPI]
1417 { off }
1419 pnpbios= [ISAPNP]
1420 { on | off | curr | res | no-curr | no-res }
1422 pnp_reserve_irq=
1423 [ISAPNP] Exclude IRQs for the autoconfiguration
1425 pnp_reserve_dma=
1426 [ISAPNP] Exclude DMAs for the autoconfiguration
1428 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1429 Ranges are in pairs (I/O port base and size).
1431 pnp_reserve_mem=
1432 [ISAPNP] Exclude memory regions for the
1433 autoconfiguration.
1434 Ranges are in pairs (memory base and size).
1436 print-fatal-signals=
1437 [KNL] debug: print fatal signals
1438 print-fatal-signals=1: print segfault info to
1439 the kernel console.
1440 default: off.
1442 printk.time= Show timing data prefixed to each printk message line
1443 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1445 profile= [KNL] Enable kernel profiling via /proc/profile
1446 Format: [schedule,]<number>
1447 Param: "schedule" - profile schedule points.
1448 Param: <number> - step/bucket size as a power of 2 for
1449 statistical time based profiling.
1450 Param: "sleep" - profile D-state sleeping (millisecs).
1451 Requires CONFIG_SCHEDSTATS
1452 Param: "kvm" - profile VM exits.
1454 processor.max_cstate= [HW,ACPI]
1455 Limit processor to maximum C-state
1456 max_cstate=9 overrides any DMI blacklist limit.
1458 processor.nocst [HW,ACPI]
1459 Ignore the _CST method to determine C-states,
1460 instead using the legacy FADT method
1462 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1463 before loading.
1464 See Documentation/ramdisk.txt.
1466 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1467 probe for; one of (bare|imps|exps|lifebook|any).
1468 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1469 per second.
1470 psmouse.resetafter= [HW,MOUSE]
1471 Try to reset the device after so many bad packets
1472 (0 = never).
1473 psmouse.resolution=
1474 [HW,MOUSE] Set desired mouse resolution, in dpi.
1475 psmouse.smartscroll=
1476 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1477 0 = disabled, 1 = enabled (default).
1479 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1480 Format:
1481 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1483 pt. [PARIDE]
1484 See Documentation/paride.txt.
1486 pty.legacy_count=
1487 [KNL] Number of legacy pty's. Overwrites compiled-in
1488 default number.
1490 quiet [KNL] Disable most log messages
1492 r128= [HW,DRM]
1494 raid= [HW,RAID]
1495 See Documentation/md.txt.
1497 ramdisk_blocksize= [RAM]
1498 See Documentation/ramdisk.txt.
1500 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1501 See Documentation/ramdisk.txt.
1503 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1504 RCU callbacks to process in one batch.
1506 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1507 RCU callbacks over which batch limiting is disabled.
1509 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1510 RCU callbacks below which batch limiting is re-enabled.
1512 rdinit= [KNL]
1513 Format: <full_path>
1514 Run specified binary instead of /init from the ramdisk,
1515 used for early userspace startup. See initrd.
1517 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1518 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1519 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1521 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1523 reservetop= [X86-32]
1524 Format: nn[KMG]
1525 Reserves a hole at the top of the kernel virtual
1526 address space.
1528 reset_devices [KNL] Force drivers to reset the underlying device
1529 during initialization.
1531 resume= [SWSUSP]
1532 Specify the partition device for software suspend
1534 resume_offset= [SWSUSP]
1535 Specify the offset from the beginning of the partition
1536 given by "resume=" at which the swap header is located,
1537 in <PAGE_SIZE> units (needed only for swap files).
1538 See Documentation/power/swsusp-and-swap-files.txt
1540 retain_initrd [RAM] Keep initrd memory after extraction
1542 rhash_entries= [KNL,NET]
1543 Set number of hash buckets for route cache
1545 riscom8= [HW,SERIAL]
1546 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1548 ro [KNL] Mount root device read-only on boot
1550 root= [KNL] Root filesystem
1552 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1553 mount the root filesystem
1555 rootflags= [KNL] Set root filesystem mount option string
1557 rootfstype= [KNL] Set root filesystem type
1559 rootwait [KNL] Wait (indefinitely) for root device to show up.
1560 Useful for devices that are detected asynchronously
1561 (e.g. USB and MMC devices).
1563 root_plug.vendor_id=
1564 [ROOTPLUG] Override the default vendor ID
1566 root_plug.product_id=
1567 [ROOTPLUG] Override the default product ID
1569 root_plug.debug=
1570 [ROOTPLUG] Enable debugging output
1572 rw [KNL] Mount root device read-write on boot
1574 S [KNL] Run init in single mode
1576 sa1100ir [NET]
1577 See drivers/net/irda/sa1100_ir.c.
1579 sbni= [NET] Granch SBNI12 leased line adapter
1581 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1582 Format: <io>[,<timeout>[,<isapnp>]]
1584 scsi_debug_*= [SCSI]
1585 See drivers/scsi/scsi_debug.c.
1587 scsi_default_dev_flags=
1588 [SCSI] SCSI default device flags
1589 Format: <integer>
1591 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1592 Format: <vendor>:<model>:<flags>
1593 (flags are integer value)
1595 scsi_logging= [SCSI]
1597 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1598 discovered. async scans them in kernel threads,
1599 allowing boot to proceed. none ignores them, expecting
1600 user space to do the scan.
1602 selinux [SELINUX] Disable or enable SELinux at boot time.
1603 Format: { "0" | "1" }
1604 See security/selinux/Kconfig help text.
1605 0 -- disable.
1606 1 -- enable.
1607 Default value is set via kernel config option.
1608 If enabled at boot time, /selinux/disable can be used
1609 later to disable prior to initial policy load.
1611 selinux_compat_net =
1612 [SELINUX] Set initial selinux_compat_net flag value.
1613 Format: { "0" | "1" }
1614 0 -- use new secmark-based packet controls
1615 1 -- use legacy packet controls
1616 Default value is 0 (preferred).
1617 Value can be changed at runtime via
1618 /selinux/compat_net.
1620 serialnumber [BUGS=X86-32]
1622 shapers= [NET]
1623 Maximal number of shapers.
1625 sim710= [SCSI,HW]
1626 See header of drivers/scsi/sim710.c.
1628 simeth= [IA-64]
1629 simscsi=
1631 slram= [HW,MTD]
1633 slub_debug[=options[,slabs]] [MM, SLUB]
1634 Enabling slub_debug allows one to determine the
1635 culprit if slab objects become corrupted. Enabling
1636 slub_debug can create guard zones around objects and
1637 may poison objects when not in use. Also tracks the
1638 last alloc / free. For more information see
1639 Documentation/vm/slub.txt.
1641 slub_max_order= [MM, SLUB]
1642 Determines the maximum allowed order for slabs.
1643 A high setting may cause OOMs due to memory
1644 fragmentation. For more information see
1645 Documentation/vm/slub.txt.
1647 slub_min_objects= [MM, SLUB]
1648 The minimum number of objects per slab. SLUB will
1649 increase the slab order up to slub_max_order to
1650 generate a sufficiently large slab able to contain
1651 the number of objects indicated. The higher the number
1652 of objects the smaller the overhead of tracking slabs
1653 and the less frequently locks need to be acquired.
1654 For more information see Documentation/vm/slub.txt.
1656 slub_min_order= [MM, SLUB]
1657 Determines the mininum page order for slabs. Must be
1658 lower than slub_max_order.
1659 For more information see Documentation/vm/slub.txt.
1661 slub_nomerge [MM, SLUB]
1662 Disable merging of slabs with similar size. May be
1663 necessary if there is some reason to distinguish
1664 allocs to different slabs. Debug options disable
1665 merging on their own.
1666 For more information see Documentation/vm/slub.txt.
1668 smart2= [HW]
1669 Format: <io1>[,<io2>[,...,<io8>]]
1671 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1672 attempt to substitute SMP alternatives once at boot.
1674 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1675 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1676 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1677 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1678 smsc-ircc2.ircc_irq= [HW] IRQ line
1679 smsc-ircc2.ircc_dma= [HW] DMA channel
1680 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1681 0: Toshiba Satellite 1800 (GP data pin select)
1682 1: Fast pin select (default)
1683 2: ATC IRMode
1685 snd-ad1816a= [HW,ALSA]
1687 snd-ad1848= [HW,ALSA]
1689 snd-ali5451= [HW,ALSA]
1691 snd-als100= [HW,ALSA]
1693 snd-als4000= [HW,ALSA]
1695 snd-azt2320= [HW,ALSA]
1697 snd-cmi8330= [HW,ALSA]
1699 snd-cmipci= [HW,ALSA]
1701 snd-cs4231= [HW,ALSA]
1703 snd-cs4232= [HW,ALSA]
1705 snd-cs4236= [HW,ALSA]
1707 snd-cs4281= [HW,ALSA]
1709 snd-cs46xx= [HW,ALSA]
1711 snd-dt019x= [HW,ALSA]
1713 snd-dummy= [HW,ALSA]
1715 snd-emu10k1= [HW,ALSA]
1717 snd-ens1370= [HW,ALSA]
1719 snd-ens1371= [HW,ALSA]
1721 snd-es968= [HW,ALSA]
1723 snd-es1688= [HW,ALSA]
1725 snd-es18xx= [HW,ALSA]
1727 snd-es1938= [HW,ALSA]
1729 snd-es1968= [HW,ALSA]
1731 snd-fm801= [HW,ALSA]
1733 snd-gusclassic= [HW,ALSA]
1735 snd-gusextreme= [HW,ALSA]
1737 snd-gusmax= [HW,ALSA]
1739 snd-hdsp= [HW,ALSA]
1741 snd-ice1712= [HW,ALSA]
1743 snd-intel8x0= [HW,ALSA]
1745 snd-interwave= [HW,ALSA]
1747 snd-interwave-stb=
1748 [HW,ALSA]
1750 snd-korg1212= [HW,ALSA]
1752 snd-maestro3= [HW,ALSA]
1754 snd-mpu401= [HW,ALSA]
1756 snd-mtpav= [HW,ALSA]
1758 snd-nm256= [HW,ALSA]
1760 snd-opl3sa2= [HW,ALSA]
1762 snd-opti92x-ad1848=
1763 [HW,ALSA]
1765 snd-opti92x-cs4231=
1766 [HW,ALSA]
1768 snd-opti93x= [HW,ALSA]
1770 snd-pmac= [HW,ALSA]
1772 snd-rme32= [HW,ALSA]
1774 snd-rme96= [HW,ALSA]
1776 snd-rme9652= [HW,ALSA]
1778 snd-sb8= [HW,ALSA]
1780 snd-sb16= [HW,ALSA]
1782 snd-sbawe= [HW,ALSA]
1784 snd-serial= [HW,ALSA]
1786 snd-sgalaxy= [HW,ALSA]
1788 snd-sonicvibes= [HW,ALSA]
1790 snd-sun-amd7930=
1791 [HW,ALSA]
1793 snd-sun-cs4231= [HW,ALSA]
1795 snd-trident= [HW,ALSA]
1797 snd-usb-audio= [HW,ALSA,USB]
1799 snd-via82xx= [HW,ALSA]
1801 snd-virmidi= [HW,ALSA]
1803 snd-wavefront= [HW,ALSA]
1805 snd-ymfpci= [HW,ALSA]
1807 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1808 See Documentation/sonypi.txt
1810 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1811 See Documentation/specialix.txt.
1813 spia_io_base= [HW,MTD]
1814 spia_fio_base=
1815 spia_pedr=
1816 spia_peddr=
1818 sscape= [HW,OSS]
1819 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1821 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1822 See Documentation/scsi/st.txt.
1824 st0x= [HW,SCSI]
1825 See header of drivers/scsi/seagate.c.
1827 sti= [PARISC,HW]
1828 Format: <num>
1829 Set the STI (builtin display/keyboard on the HP-PARISC
1830 machines) console (graphic card) which should be used
1831 as the initial boot-console.
1832 See also comment in drivers/video/console/sticore.c.
1834 sti_font= [HW]
1835 See comment in drivers/video/console/sticore.c.
1837 stifb= [HW]
1838 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1840 sunrpc.pool_mode=
1841 [NFS]
1842 Control how the NFS server code allocates CPUs to
1843 service thread pools. Depending on how many NICs
1844 you have and where their interrupts are bound, this
1845 option will affect which CPUs will do NFS serving.
1846 Note: this parameter cannot be changed while the
1847 NFS server is running.
1849 auto the server chooses an appropriate mode
1850 automatically using heuristics
1851 global a single global pool contains all CPUs
1852 percpu one pool for each CPU
1853 pernode one pool for each NUMA node (equivalent
1854 to global on non-NUMA machines)
1856 swiotlb= [IA-64] Number of I/O TLB slabs
1858 switches= [HW,M68k]
1860 sym53c416= [HW,SCSI]
1861 See header of drivers/scsi/sym53c416.c.
1863 sysrq_always_enabled
1864 [KNL]
1865 Ignore sysrq setting - this boot parameter will
1866 neutralize any effect of /proc/sys/kernel/sysrq.
1867 Useful for debugging.
1869 t128= [HW,SCSI]
1870 See header of drivers/scsi/t128.c.
1872 tdfx= [HW,DRM]
1874 thash_entries= [KNL,NET]
1875 Set number of hash buckets for TCP connection
1877 thermal.act= [HW,ACPI]
1878 -1: disable all active trip points in all thermal zones
1879 <degrees C>: override all lowest active trip points
1881 thermal.crt= [HW,ACPI]
1882 -1: disable all critical trip points in all thermal zones
1883 <degrees C>: lower all critical trip points
1885 thermal.nocrt= [HW,ACPI]
1886 Set to disable actions on ACPI thermal zone
1887 critical and hot trip points.
1889 thermal.off= [HW,ACPI]
1890 1: disable ACPI thermal control
1892 thermal.psv= [HW,ACPI]
1893 -1: disable all passive trip points
1894 <degrees C>: override all passive trip points to this value
1896 thermal.tzp= [HW,ACPI]
1897 Specify global default ACPI thermal zone polling rate
1898 <deci-seconds>: poll all this frequency
1899 0: no polling (default)
1901 time Show timing data prefixed to each printk message line
1902 [deprecated, see 'printk.time']
1904 tipar.timeout= [HW,PPT]
1905 Set communications timeout in tenths of a second
1906 (default 15).
1908 tipar.delay= [HW,PPT]
1909 Set inter-bit delay in microseconds (default 10).
1911 tmc8xx= [HW,SCSI]
1912 See header of drivers/scsi/seagate.c.
1914 tmscsim= [HW,SCSI]
1915 See comment before function dc390_setup() in
1916 drivers/scsi/tmscsim.c.
1918 tp720= [HW,PS2]
1920 trix= [HW,OSS] MediaTrix AudioTrix Pro
1921 Format:
1922 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1924 turbografx.map[2|3]= [HW,JOY]
1925 TurboGraFX parallel port interface
1926 Format:
1927 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1928 See also Documentation/input/joystick-parport.txt
1930 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1931 See header of drivers/scsi/u14-34f.c.
1933 uart401= [HW,OSS]
1934 Format: <io>,<irq>
1936 uart6850= [HW,OSS]
1937 Format: <io>,<irq>
1939 uhci-hcd.ignore_oc=
1940 [USB] Ignore overcurrent events (default N).
1941 Some badly-designed motherboards generate lots of
1942 bogus events, for ports that aren't wired to
1943 anything. Set this parameter to avoid log spamming.
1944 Note that genuine overcurrent events won't be
1945 reported either.
1947 usbcore.autosuspend=
1948 [USB] The autosuspend time delay (in seconds) used
1949 for newly-detected USB devices (default 2). This
1950 is the time required before an idle device will be
1951 autosuspended. Devices for which the delay is set
1952 to a negative value won't be autosuspended at all.
1954 usbhid.mousepoll=
1955 [USBHID] The interval which mice are to be polled at.
1957 vdso= [X86-32,SH,x86-64]
1958 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
1959 vdso=1: enable VDSO (default)
1960 vdso=0: disable VDSO mapping
1962 vector= [IA-64,SMP]
1963 vector=percpu: enable percpu vector domain
1965 video= [FB] Frame buffer configuration
1966 See Documentation/fb/modedb.txt.
1968 vga= [BOOT,X86-32] Select a particular video mode
1969 See Documentation/i386/boot.txt and
1970 Documentation/svga.txt.
1971 Use vga=ask for menu.
1972 This is actually a boot loader parameter; the value is
1973 passed to the kernel using a special protocol.
1975 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1976 size of <nn>. This can be used to increase the
1977 minimum size (128MB on x86). It can also be used to
1978 decrease the size and leave more room for directly
1979 mapped kernel RAM.
1981 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1982 Format: <command>
1984 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1985 Format: <command>
1987 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1988 Format: <command>
1990 waveartist= [HW,OSS]
1991 Format: <io>,<irq>,<dma>,<dma2>
1993 wd33c93= [HW,SCSI]
1994 See header of drivers/scsi/wd33c93.c.
1996 wd7000= [HW,SCSI]
1997 See header of drivers/scsi/wd7000.c.
1999 wdt= [WDT] Watchdog
2000 See Documentation/watchdog/wdt.txt.
2002 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2003 xd_geo= See header of drivers/block/xd.c.
2005 xirc2ps_cs= [NET,PCMCIA]
2006 Format:
2007 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2009 norandmaps Don't use address space randomization
2010 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2012 ______________________________________________________________________
2014 TODO:
2016 Add documentation for ALSA options.
2017 Add more DRM drivers.